The present invention relates to golf clubs and more particularly to a golf club having an improved face or ball striking surface.
A typical set of golf clubs includes a putter, a series of irons and a series of woods. The clubs have heads of varying loft. The clubs may also have varying shaft lengths. As the loft increases, golf ball distance will generally decrease and trajectory height will increase. With irons and woods, the ball striking face is typically grooved to increase friction between the ball and club face. The grooving tends to impart spin to the ball. Spin helps to maintain the ball on line and affects the aerodynamics of ball flight. The majority of putters in use today have a relatively smooth face. In addition, the face has a minimal loft angle. Generally, the golf ball will skid or slide for a short distance after being struck by the putter. Friction between the ball and putting surface eventually imparts spin to the ball. This skidding or sliding action can result in the ball going off line. While normal manufacturing tolerances have heretofore been thought to be sufficient, deviations in flatness of the putter face can result in off line putts.
Various attempts have been made to improve the ball striking surface of golf clubs. One example is found in U.S. Pat. No. 4,768,787 which issued on Sept. 6, 1988 to Shira. As shown therein, a golf club has a metallic golfball striking surface which includes a plurality of hard particles embedded therein which increase the surface coefficient of friction. Portions of the particles protrude above the surface so as to provide greater frictional grip between the golfball striking surface and the golfball.
Other examples of attempts to increase the coefficient of friction of the ball striking surface may be found in U.S. Pat. No. 669,864 entitled GOLF CLUB and issued on Mar. 12, 1901 to Simpson; U.S. Pat. No. 722,927 entitled GOLF STICK and issued on Mar. 17, 1903 to Swift; U.S. Pat. No. 749,174 entitled PUTTER and issued on Jan. 12, 1904 to Davis; U.S. Pat. No. 4,754,970 entitled GOLF CLUB SET and issued on July 5, 1988 to Kobayashi; and U.S. Pat. No. 4,754,971 entitled GOLF CLUB SET and issued on July 5, 1988 to Kobayashi. Each of the Kobayashi patents disclose golf club sets wherein the striking surface of the club head has a coefficient of friction which varies with the angle of the loft of the club. Patents such as Davis are representative of prior approaches which roughen the ball striking surface to increase the friction between the ball and the club head.
Heretofore, manufacturing and finishing processes especially on golf putter faces, have been inadequate. Present flatness tolerances even though within the range of .+-.0.005 to 0.110 inches, result in off line putts which are magnified by the required stroke length to achieve a desired distance.
A need exists, therefore, for an improved finishing method and golf ball striking surface which provides increased accuracy, an increased coefficient of friction to eliminate skidding, a reduced surface contact area to achieve an improved feel, and which permits the use of a reduced stroke length necessary to achieve a correct or desired distance.